Publish notifications about mails to the fedmsg bus.

Enable this by adding the following to your mailman.cfg file:

[archiver.fedmsg]
# The class implementing the IArchiver interface.
class: mailman3_fedmsg_plugin.Archiver
enable: yes

You can exclude certain lists from fedmsg publication by adding them to a 'mailman.excluded_lists' list in /etc/fedmsg.d/:

config = {
    'mailman.excluded_lists': ['bugzilla', 'commits'],
}